Neuromuscular coordination of squat lifting, II: Individual differences.
Neuromuscular coordination of squat lifting, II: Individual differences.
复制标题
深蹲举重的神经肌肉协调，II：个体差异。
作者：
John P. Scholz;Amy Gross McMillan
背景和目的
本文报告了通过对作者在本期的配套文章中报告的数据进行扩展分析而确定的蹲举协调性（即关节运动和肌肉活动的相对时间）的个体差异。
科目
根据载荷加速过程中膝-腰椎相对运动图的定性差异，从15例受试者的原始样本中确定了两个事后组，每组6例受试者。
方法
受试者提出了一个板条箱包含15%至75%的最大起重能力使用对称蹲举技术。运动运动学数据由摄像机获得，股外侧肌和竖脊肌的肌电图（EMG）活动由表面EMG记录。运动学和通过肌电图和运动学数据得出的协调测量进行了检查组间差异。
结果
第2组中的受试者限制腰椎运动在负荷加速过程中的所有负荷解除，而第1组中的限制腰椎运动时，解除最重的负荷。这些差异是明显的定性，通过膝-腰椎相对运动图，和定量，通过在电梯早期的关节运动的相对时间的措施。在初始载荷加速后，两个事后组的载荷对这些关节协调的影响相同。其他运动学测量也发现这些组之间的显着差异。
结论与讨论
尽管有关于如何举起重物的具体说明，但在蹲举的初始加速阶段，个体受试者的关节协调方式不同。虽然2名受试者的数据难以分类，因此未纳入这些分析，但对负荷增加的协调反应的个体差异可分为两种模式。这两种主要的模式是否对举重过程中关节的应力有影响还有待确定。
BACKGROUND AND PURPOSE
This article reports individual differences in the coordination (ie, the relative timing of joint movements and muscle activity) of squat lifting identified by extended analysis of data reported in the authors' companion article in this issue.
SUBJECTS
Two post hoc groups of 6 subjects each were identified from the original sample of 15 subjects based on qualitative differences in knee-lumbar spine relative motion plots during load acceleration.
METHODS
Subjects lifted a crate containing 15% to 75% of their maximum lifting capacity using a symmetrical squat-lift technique. Movement kinematic data were obtained with videography, and the electromyographic (EMG) activity of the vastus lateralis and erector spinae muscles was recorded with surface EMG. Measurements of coordination derived both kinematically and via EMG and the kinematic data were examined for group differences.
RESULTS
Subjects in group 2 limited lumbar spine motion during load acceleration for all loads lifted, whereas those in group 1 limited lumbar spine motion more when lifting the heaviest loads. These differences were obvious both qualitatively, via knee-lumbar spine relative motion plots, and quantitatively, via measures of the relative timing of joint motions early in the lift. The effect of load on the coordination of these joints was the same for both post hoc groups after initial load acceleration. Significant differences in other kinematic measurements were also found between these groups.
CONCLUSION AND DISCUSSION
Despite specific instructions about how to lift the load, individual subjects coordinated their joints differently during the initial, accelerative phase of squat lifting. Individual differences in coordination in response to load increases could be categorized into two patterns, although the data of 2 subjects were difficult to categorize and thus not included in these analyses. Whether the two dominant patterns have consequences for stress to the joints during lifting remains to be determined.